Published: 12/13/07

WEDNESDAY, Dec.12 (HealthDay News) -- Merck & Co. has recalled 1.2 million doses of a common childhood vaccine due to potential contamination during the manufacturing process. But, the vaccine does not pose a health threat, U.S. health officials announced late Wednesday.

The company voluntarily recalled two lots of the Haemophilus influenzae type B (Hib) vaccine. Haemophilus influenzae is a group of bacteria that may cause different types of infections in infants and children. They include ear, eye, or sinus infections and pneumonia. The more serious but rare strain can cause meningitis and a life-threatening infection called epiglottitis.

The Hib vaccine is recommended for all children under 5 and is usually given in a three-shot series, starting at 2 months of age.

"The CDC and FDA learned this week that Merck, one of two companies that provide Hib vaccine, is recalling certain lots of the vaccine," Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention, said during a late afternoon teleconference. "Right now, this is not a health-threatening situation for children."

There have been no reported cases of adverse effects with the Hib vaccine, Gerberding said. "The recall has nothing to do with the potency of the vaccine, so children who have received the vaccine are protected," she said.

Gerberding noted that Haemophilus influenzae type B is a bacteria and has nothing to do with influenza virus.

Before the Hib vaccine, there were about 20,000 cases of Hib diseases in the United States each year, leading to about 1,000 deaths, according to the CDC.

"But thanks to the vaccine there are fewer than 100 documented cases of Hib disease in the entire United States each year -- a reduction of over 99 percent," Gerberding said.

The vaccine is made by both Merck and Sanofi Pasteur. The recall involves lots of Merck's PedvaxHIB and Comvax shipped after April 2007.

It's not known how many of the 1.2 million doses may have been given to children. But even children who received a vaccine from one of the recalled lots are not at risk of any health problems, Gerberding said.

Gerberding expects the recall will result in shortages of the vaccine, but she doesn't expect any increase in disease because so many children have been vaccinated.

"We are sorry for parents who will be inconvenienced," she said.

Merck identified the problem during routine testing of the manufacturing process at a plant in Pennsylvania, Dr. Norman Baylor, director of the U.S. Food and Drug Administration's Office of Vaccine Research and Review, said during the teleconference.

"Merck identified an issue that creates the potential for microorganisms to survive a sterilization step performed during manufacturing," Baylor said. "No documented contamination of the vaccine has been found."

Parents whose children were recently vaccinated against Hib can look for skin bumps or abscesses at the site of the injection, which could indicate a potential problem, said Dr. Anne Schuchat, the CDC's director of the National Center for Immunization and Respiratory Diseases. But she did not specify what those problems might be.

"These kinds of things might emerge up to a week after a vaccination," Schuchat said. "But we don't have any reports of those."

The CDC is reviewing the Hib vaccine supply throughout the country to see what can be done to alleviate any shortage that occurs, she added.

More information

For more Haemophilus influenzae infections, visit the U.S. Centers for Disease Control and Prevention.

Last reviewed: 12/13/2007 | Last updated: 12/13/2007